Add standalone repo scaffolding (README, packaging, CI)

Adds the release/CI machinery bos-settings already has in its own repo:
Forgejo package.yml (tag -> build -> publish to [breadway]) and
mirror.yml (Forgejo -> GitHub). PKGBUILD updated for the flattened
layout and dropped -p breadhelp now that this isn't a workspace member.

packaging/PKGBUILD

@@ -5,7 +5,7 @@ pkgver=0.1.0
 pkgrel=1
 pkgdesc="Onboarding and help center for Bread OS"
 arch=('x86_64')
-url="https://github.com/Breadway/bos"
+url="https://github.com/Breadway/breadhelp"
 license=('MIT')
 # Some Rust deps (ring/mlua) build vendored C/asm into static archives; makepkg's
 # default -flto=auto emits GCC LTO bitcode the Rust (lld) link cannot read,
@@ -21,20 +21,20 @@ sha256sums=('SKIP')
 
 build() {
   cd "${srcdir}/${pkgname}-${pkgver}"
-  cargo build --release --locked -p breadhelp
+  cargo build --release --locked
 }
 
 check() {
   cd "${srcdir}/${pkgname}-${pkgver}"
-  cargo test --release --locked -p breadhelp
+  cargo test --release --locked
 }
 
 package() {
   cd "${srcdir}/${pkgname}-${pkgver}"
   install -Dm755 target/release/breadhelp "${pkgdir}/usr/bin/breadhelp"
-  install -Dm644 packaging/arch/breadhelp/breadhelp.desktop \
+  install -Dm644 packaging/breadhelp.desktop \
     "${pkgdir}/usr/share/applications/breadhelp.desktop"
   install -d "${pkgdir}/usr/share/breadhelp"
-  cp -r breadhelp/content "${pkgdir}/usr/share/breadhelp/content"
+  cp -r content "${pkgdir}/usr/share/breadhelp/content"
   install -Dm644 LICENSE "${pkgdir}/usr/share/licenses/${pkgname}/LICENSE"
 }

packaging/README.md

@@ -0,0 +1,26 @@
+Arch packaging
+==============
+
+`PKGBUILD` builds and installs `breadhelp` from source.
+
+## Local build
+
+```bash
+makepkg -si
+```
+
+## Before publishing to [breadway] repo
+
+1. Tag a release on GitHub.
+2. Update `pkgver` to match the tag.
+3. Update `source` to the release tarball URL.
+4. Run `updpkgsums` (or manually set `sha256sums`).
+
+## Runtime dependencies
+
+| Package | Required | Notes |
+|---------|----------|-------|
+| `gtk4` | yes | UI toolkit |
+| `glib2` | yes | always |
+| `gtk4-layer-shell` | yes | tour overlay (dim mask + spotlight callout) |
+| `snapper` | optional | create-backup one-click fix |